TRB Assistant Professor Previous Year Question Paper - 4

Question: 16

The echo is produced by the sound waves due to

(A) the reflection of sound

(B) the refraction of sound

(C) the scattering of sound

(D) none of these

Question: 17

When we speak into a microphone, what type of vibrations the diaphragm executes?

(A) Free

(B) Resonant

(C) Forced

(D) Motion

Question: 18

The velocity of light in water is

(A) 3x10⁸ m/s

(B) 1.24x10⁸ m/s

(C) 2.25x10⁸ m/s

(D) 1.96x10⁸ m/s

Question: 19

A moderator is used in nuclear reactors in order to

(A) increase the number of neutrons

(B) decrease the number of neutrons

(C) slow down the speed of neutrons

(D) accelerate the neutrons

Question: 20

In SONAR, we use

(A) radio waves

(B) audible sound waves

(C) ultrasonic waves

(D) infrasonic waves